For example, as represented in Patent Documents 1 and 2, a thrust increasing device is mounted on a jet engine, and obtains thrust by supplying fuel to a jet flow and burning the fuel again. Such a thrust increasing device is provided with a fuel injector that ejects fuel into a jet flow, an ignition device that is disposed downstream from the fuel injector, a cylindrical duct that surrounds a combustion region, and a flame holder that is disposed in the duct.